1. Field of the Invention
The invention relates to a converting device, and more particularly to a voltage converting device.
2. Description of the Related Art
FIG. 1 and FIG. 2 illustrate a conventional voltage converting device that includes a first stage circuit 11, a second stage circuit 12 and a third stage circuit 13.
The first stage circuit 11 receives and converts complementary input signals DIN, DIP into complementary first-stage output signals D1, D1B, where each of the input signals DIN, DIP has a voltage magnitude ranging between VDD and GND, and each of the first-stage output signals D1, D1B has a voltage magnitude ranging between VDD and VNN, as shown in FIG. 1.
The second stage circuit 12 receives and converts either one of the first-stage output signals D1, D1B into complementary second-stage output signals D2, D2B each having a voltage magnitude ranging between GND and VNN, as shown in FIG. 1.
The third stage circuit 13 receives and converts the second-stage output signals D2, D2B into complementary output signals OUT, OUTB each having a voltage magnitude ranging between GND and VEE, as shown in FIG. 1.
When the input signals are directly converted into the output signals with VDD=1.5V and VEE=−6V, the maximum voltage applied to the circuit components is 7.5V. When voltage conversion from the input signals to the output signals is divided into three conversion circuit stages as shown in FIG. 2 with GND=0V and VNN=−3V, the first-stage output signals D1, DIB range between 1.5V and −3V, the second-stage output signals D2, D2B range between 0V and −3V, and the output signals OUT, OUTB range between 0V and −6V, thereby reducing the maximum voltage applied to the circuit components to 6V, and circuit components with lower rated voltage ranges may be used in the circuit.
However, more conversion circuit stages may result in more power consumption.